Republican Sen. John McCain, shown in a 2016 file photo, is recuperating in Phoenix after surgery to remove a blood clot from over his left eye. Doctors said such clots on the brain are not uncommon, but McCain’s 2-inch clot was “quite large.” (Photo by Keerthi Vedantam/Cronkite News)

WASHINGTON – Sen. Jeff Flake said fellow Arizona Sen. John McCain “sounded great” in a phone conversation Monday, just three days after McCain underwent surgery to have a blood clot removed from above his left eye.

“I hope that we can get him back here as quickly as possible, we need him,” Flake said of his fellow Republican Tuesday after a news conference in Washington.

McCain and officials at the Mayo Clinic Hospital in Phoenix have said little about the procedure, except that after an annual physical doctors removed a “5-cm blood clot during a minimally invasive craniotomy with an eyebrow incision” Friday at the Mayo Clinic. The statement went on to say that the procedure went “very well” and McCain was resting at home in good condition and would stay in Arizona for at least a week while he recovers.

Calls to both McCain’s office and the hospital seeking updates on the senator’s progress Tuesday were not returned.

Medical experts said blood clots in the brain are not unusual, but that the size of McCain’s – just about 2 inches – is unusual and that its still-undetermined cause could lead to further implications.

“It sounded like there was little question that it needed to be operated on,” said Dr. Sanjay Gupta, a neurosurgeon who covers medical issues for CNN.

Dr. Walter Jean, a professor of neurosurgery at George Washington University, explained that the craniotomy McCain underwent would have required an “opening of the skull.” He said that blood clots in the brain are not uncommon but that a “5-centimeter one is quite large” and that it is a “pretty big deal.”

Gupta, agreed that the 5-centimeter clot is a “sizable collection of blood.”

Jean said that the cause of the clot is the “most interesting thing” about this.

“They evacuated the clot and they sent the specimens to the pathologist,” Jean said. “That tells me, and this is somewhat speculative, that tells me that they think that there is a cause of the blood clot that is, at this point, still unknown.”

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Gupta talked about McCain’s history of melanoma.

“If they do find evidence of melanoma there, then there’s going to be discussion as to what further types of therapies he may need,” Gupta said.

McCain’s office released a statement over the weekend that said he “received excellent treatment at Mayo Clinic Hospital in Phoenix, and appreciates the tremendous professionalism and care by its doctors and staff. He is in good spirits and recovering comfortably at home with his family.”

But while he’s home, McCain is not entirely removed from Washington, issuing statements as a Republican plan to replace the Affordable Care Act crumbled over the last few days.

McCain released a statement through his office Monday calling on the Senate to take a step back and “hold hearings, receive input from members of both parties, and heed the recommendations of our nation’s governors” on a replacement bill. He blamed problems with the current health care law on Democrats who forced it through Congress with no bipartisan support.

Senate Majority Leader Mitch McConnell said after McCain’s surgery that he would hold off on a vote until the Arizona Republican could return. That went out the window this week, when McConnell conceded that he did not have the votes to win a preliminary vote on health care reform, and vowed instead to move toward a vote that repeals the Affordable Care Act, or Obamacare, without having a replacement immediately in place.

It was unclear Tuesday whether that vote would hold for McCain.

Both Gupta and Jean could not say what McCain’s recovery period would be for a procedure of this type, with Jean saying it is “highly dependent on how the blood clot came about.”